Mark protected variable as thread safe in EcalBarrelGeometry

Use the cms specific annotation to mark a protected member variable
as thread safe. This will keep the static analyzer from complaining
about this class.
Mark protected variable as thread safe in EcalEndcapGeometry

Use the cms specific annotation to mark a protected member variable
as thread safe. This will keep the static analyzer from complaining
about this class.
Merge pull request #4166 from Dr15Jones/markAsThreadSafeGeometryEcalAlgo

Mark as thread safe classes from Geometry/EcalAlgo
Merge pull request #4168 from cms-sw/CMSSW_7_2_X

Forward port CMSSW_7_2_X into CMSSW_7_2_ROOT6_X.